Ul scheduling timing in tdd with 1 ms tti and reduced processing time

ABSTRACT

Systems and methods are disclosed for determining and utilizing uplink scheduling timing for reduced processing time. In some embodiments, a method of operation of a wireless device in a cellular communications network comprises receiving an uplink grant in a Transmission Time Interval (TTI) n, determining an uplink scheduling timing l based on a configured Time Division Duplexing (TDD) uplink/downlink configuration, and transmitting, in a TTI n+I, an uplink transmission in accordance with the uplink grant received in the TTI n. The uplink scheduling timing I is a number of TTIs that is larger than or equal to a predefined minimum uplink scheduling timing value such that n+I is an uplink TTI and the predefined minimum uplink scheduling timing value is 2 or 3.

RELATED APPLICATIONS

This application claims the benefit of provisional patent applicationSer. No. 62/374,446, filed Aug. 12, 2016, the disclosure of which ishereby incorporated herein by reference in its entirety.

TECHNICAL FIELD

The present disclosure relates to uplink scheduling timing in a TimeDivision Duplexing (TDD) system.

BACKGROUND

In Third Generation Partnership Project (3GPP) Technical Specification(TS) 36.211, three radio frame structures are supported. Frame Structure(FS) type 1 (FS 1) is applicable to Frequency Division Duplexing (FDD)only, FS type 2 (FS 2) is applicable to Time Division Duplexing (TDD)only, and FS type 3 (FS 3) is applicable to License Assisted Access(LAA) secondary cell operation only.

With FS 2 for TDD, each radio frame of length 10 milliseconds (ms)consists of two half-frames of length 5 ms each. Each half-frameconsists of five Subframes (SFs) of length 1 ms. Each SF is defined bytwo slots of length 0.5 ms each. Within each radio frame, a subset ofSFs are reserved for uplink transmissions, and the remaining SFs areallocated for downlink transmissions, or for special SFs, where theswitch between downlink and uplink occurs.

As shown in Table 1, copied from 3GPP TS 36.211 V13.0.0, seven differentdownlink/uplink configurations are supported for FS 2. Here, “D” denotesa downlink SF, “U” denotes an uplink SF, and “S” represents a specialSF. Configurations 0, 1, 2, and 6 have 5 ms downlink-to-uplinkswitch-point periodicity, with the special SF existing in both SF 1 andSF 6. Configurations 3, 4, and 5 have 10 ms downlink-to-uplinkswitch-point periodicity, with the special SF in SF 1 only.

TABLE 1 Downlink/Uplink Configurations DL-to-UL Switch- DL/UL point SFnumber configuration periodicity 0 1 2 3 4 5 6 7 8 9 0 5 ms D S U U U DS U U U 1 5 ms D S U U D D S U U D 2 5 ms D S U D D D S U D D 3 10 ms  DS U U U D D D D D 4 10 ms  D S U U D D D D D D 5 10 ms  D S U D D D D DD D 6 5 ms D S U U U D S U U D

A special SF is split into three parts: a downlink part (Downlink Partof a Special Subframe (DwPTS)), GP (Guard Period) and an uplink part(Uplink Part of a Special Subframe (UpPTS)). The DwPTS with duration ofmore than three symbols can be treated as a normal downlink SF for datatransmission. However, the UpPTS is not used for data transmission dueto the very short duration in the first releases of Long Term Evolution(LTE). Instead, UpPTS can be used for channel sounding or random access.In LTE Release 14 the possibility of using UpPTS for data transmissionwill be specified for a specific special SF configuration.

Typically, the downlink/uplink configuration and the configuration ofthe special SF used in a cell are signaled as part of the systeminformation, which is included in System Information Block 1 (SIB1) andbroadcasted every 80 ms within SF 5.

Hybrid Automatic Repeat Request (HARQ) timing is defined as the timerelation between the reception of data in a certain HARQ process and thetransmission of the HARQ acknowledgement. Based on this timing, thereceiver is able to know to which HARQ process a receivedacknowledgement is associated.

In TDD, an uplink HARQ acknowledgement is only allowed to be transmittedin an uplink SF, and a downlink HARQ acknowledgement is only possible inPhysical HARQ Indicator Channel (PHICH) of downlink SF and

DwPTS. The HARQ acknowledgement of a transport block in SF n istransmitted in SF n+k, where k≥4. The value of k depends on thedownlink/uplink configuration, and is given in Table 2 and Table 3 fordownlink and uplink transmissions, respectively [3GPP TS 36.213V13.0.1].

TABLE 2 HARQ Timing k for Downlink Transmissions TDD DL/UL SF index nconfiguration 0 1 2 3 4 5 6 7 8 9 0 4 6 — — — 4 6 — — — 1 7 6 — — 4 7 6— — 4 2 7 6 — 4 8 7 6 — 4 8 3 4 11 — — — 7 6 6 5 5 4 12 11 — — 8 7 7 6 54 5 12 11 — 9 8 7 6 5 4 13 6 7 7 — — — 7 7 — — 5

TABLE 3 HARQ Timing k for Uplink Transmissions TDD DL/UL SF index nconfiguration 0 1 2 3 4 5 6 7 8 9 0 — — 4 7 6 — — 4 7 6 1 — — 4 6 — — —4 6 — 2 — — 6 — — — — 6 — — 3 — — 6 6 6 — — — — — 4 — — 6 6 — — — — — —5 — — 6 — — — — — — — 6 — — 4 6 6 — — 4 7 —

Uplink scheduling timing refers to the time relation between a receiveduplink grant in downlink SF n and the uplink transmission in uplink SFn+l.

In TDD, the value of l depends on the downlink/uplink configuration. Fordownlink/uplink configurations 1-6, the values of l are given in Table4, copied from Table 8-2 in 3GPP TS 36.213 V13.0.1.

For downlink/uplink configuration 0, the value of l also depends on theUplink Index (UI) field of the uplink Downlink Control Information (DCI)transmitted in downlink SF n:

-   -   If the Most Significant Bit (MSB) (i.e., the left-most bit) of        the UI is set to 1, the value of l is obtained from Table 4;    -   If the Least Significant Bit (LSB) (i.e., the right-most bit) of        the UI is set to 1, the value of l is 7;    -   If both the MSB and the LSB of the UI are set to 1, the value of        l is 7 and the value obtained from Table 4.

Table 5 gives the uplink scheduling timing table for TDD downlink/uplinkconfiguration 0.

TABLE 4 Uplink Scheduling Timing l for Uplink Transmissions TDD DL/UL SFindex n configuration 0 1 2 3 4 5 6 7 8 9 0 4 6 4 6 1 6 4 6 4 2 4 4 3 44 4 4 4 4 5 4 6 7 7 7 7 5

TABLE 5 Uplink Scheduling Timing l for TDD Downlink/Uplink Configuration0 UL index DL/special SF UL timing, l Scheduled UL SF index 10 0 4 4 1 67 5 4 9 6 6 2 01 0 7 7 1 7 8 5 7 2 6 7 3 11 0 4, 7 4, 7 1 6, 7 7, 8 5 4,7 9, 2 6 6, 7 2, 3

Packet data latency is one of the performance metrics that vendors,operators, and also end-users (via speed test applications) regularlymeasure. Latency measurements are done in all phases of a radio accessnetwork system lifetime, when verifying a new software release or systemcomponent, when deploying a system, and when the system is in commercialoperation.

Shorter latency than previous generations of 3GPP Radio AccessTechnology (RATs) was one performance metric that guided the design ofLTE. LTE is also now recognized by the end-users to be a system thatprovides faster access to the Internet and lower data latencies thanprevious generations of mobile radio technologies.

Packet data latency is important not only for the perceivedresponsiveness of the system; it is also a parameter that indirectlyinfluences the throughput of the system. Hypertext Transfer Protocol(HTTP)/Transmission Control Protocol (TCP) is the dominating applicationand transport layer protocol suite used on the Internet today. Accordingto HTTP Archive (http://httparchive.org/trends.php), the typical size ofHTTP based transactions over the Internet are in the range of a few tensof kilobytes up to one megabyte. In this size range, the TCP slow startperiod is a significant part of the total transport period of the packetstream. During TCP slow start the performance is latency limited. Hence,improved latency can rather easily be showed to improve the averagethroughput for this type of TCP based data transactions.

Radio resource efficiency could be positively impacted by latencyreductions. Lower packet data latency could increase the number oftransmissions possible within a certain delay bound; hence, higher BlockError Rate (BLER) targets could be used for the data transmissionsfreeing up radio resources potentially improving the capacity of thesystem.

One key factor to achieve packet latency reductions is the reduction ofprocessing time for data and control signaling. In LTE Release 8, adownlink Transmission Time Interval (TTI) n corresponds to one SF oflength 1 ms and it requires 3 ms for the User Equipment device (UE) todetect the downlink assignment, decode the downlink data, and preparethe HARQ feedback to be sent in uplink. The HARQ feedback in uplink isthen sent in the uplink TTI n+4. This is valid for FDD. For TDD, thetiming is minimum n+4 but can be later depending on the TDDuplink/downlink configuration. The exact HARQ timing for TDD is given inform of tables in the specifications as mentioned earlier. Similarly, ifthe enhanced or evolved Node B (eNB) sends an uplink grant in thedownlink TTI n, the uplink transmission occurs in uplink TTI n+4 in FDDor n+4 or later for TDD.

SUMMARY

Systems and methods relating to uplink scheduling timing for reducedprocessing time are disclosed. In some embodiments, a method ofoperation of a wireless device in a cellular communications networkcomprises receiving an uplink grant in a Transmission Time Interval(TTI) n, determining an uplink scheduling timing l based on a configuredTime Division Duplexing (TDD) uplink/downlink configuration, andtransmitting, in a TTI n+l, an uplink transmission in accordance withthe uplink grant received in the TTI n. The uplink scheduling timing lis a number of TTIs that is larger than or equal to a predefined minimumuplink scheduling timing value such that n+l is an uplink TTI and thepredefined minimum uplink scheduling timing value is 2 or 3.

In some embodiments, the uplink scheduling timing l is a smallestinteger number of TTIs that is larger than or equal to a predefinedminimum uplink scheduling timing value such that n+l is an uplink TTIand the predefined minimum uplink scheduling timing value is 2 or 3.

In some embodiments, the uplink grant schedules multiple uplink TTIs forthe same wireless device.

In some embodiments, the uplink grant comprises an indication of one ormore uplink TTIs for which the uplink grant is valid.

In some embodiments, an uplink part of special Subframes (SFs) can beused for uplink data transmission, and determining the uplink schedulingtiming l comprises determining the uplink scheduling timing l in such amanner that the uplink part of the special SFs are treated as uplinkTTIs. In some other embodiments, determining the uplink schedulingtiming l comprises determining the uplink scheduling timing l in such amanner that the uplink part of the special SFs are not treated as uplinkTTIs.

In some embodiments, the configured TDD uplink/downlink configuration isLong Term Evolution (LTE) TDD uplink/downlink configuration 1, anddetermining the uplink scheduling timing l comprises determining theuplink scheduling timing l such that the uplink scheduling timing l is 3if n=0, the uplink scheduling timing l is 5 if n=1, the uplinkscheduling timing l is 3 if n=4, the uplink scheduling timing l is 3 ifn=5, the uplink scheduling timing l is 5 if n=6, and the uplinkscheduling timing l is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 2, and determining the uplinkscheduling timing l comprises determining the uplink scheduling timing lsuch that the uplink scheduling timing l is 3 if n=3, the uplinkscheduling timing l is 3 if n=4, the uplink scheduling timing l is 3 ifn=8, and the uplink scheduling timing l is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 3, and determining the uplinkscheduling timing l comprises determining the uplink scheduling timing lsuch that the uplink scheduling timing l is 3 if n=0, the uplinkscheduling timing l is 3 if n=1, the uplink scheduling timing l is 3 ifn=8, and the uplink scheduling timing l is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 4, and determining the uplinkscheduling timing l comprises determining the uplink scheduling timing lsuch that the uplink scheduling timing l is 3 if n=0, the uplinkscheduling timing l is 3 if n=8, and the uplink scheduling timing l is 3if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 5, and determining the uplinkscheduling timing l comprises determining the uplink scheduling timing lsuch that the uplink scheduling timing l is 3 if n=8 and the uplinkscheduling timing l is 3 if n=9.

In some embodiments, determining the uplink scheduling timing lcomprises determining the uplink scheduling timing l based on theconfigured TDD uplink/downlink configuration and an Uplink Index (UI)comprises the uplink grant received in the TTI n.

In some embodiments, the TTI n and the TTI n+l are 1 millisecond (ms)TTIs.

Embodiments of a wireless device for a cellular communications networkare also disclosed. In some embodiments, a wireless device for acellular communications network is adapted to receive an uplink grant ina TTI n, determine an uplink scheduling timing l based on a configuredTDD uplink/downlink configuration, and transmit, in a TTI n+l, an uplinktransmission in accordance with the uplink grant received in the TTI n.The uplink scheduling timing l is a number of TTIs that is larger thanor equal to a predefined minimum uplink scheduling timing value suchthat n+l is an uplink TTI and the predefined minimum uplink schedulingtiming value is 2 or 3.

In some embodiments, the wireless device is further adapted to performthe method of operation of a wireless device according to any otherembodiments of the method of operation of a wireless device disclosedherein.

In some embodiments, a wireless device for a cellular communicationsnetwork comprises at least one transceiver, at least one processor, andmemory comprising instructions executable by the at least one processorwhereby the wireless device is operable to receive an uplink grant in aTTI n, determine an uplink scheduling timing l based on a configured TDDuplink/downlink configuration, and transmit, in a TTI n+l, an uplinktransmission in accordance with the uplink grant received in the TTI n.The uplink scheduling timing l is a number of TTIs that is larger thanor equal to a predefined minimum uplink scheduling timing value suchthat n+l is an uplink TTI and the predefined minimum uplink schedulingtiming value is 2 or 3.

In some embodiments, a wireless device for a cellular communicationsnetwork comprises a receiving module, a determining module, and atransmitting module. The receiving module is operable to receive anuplink grant in a TTI n. The determining module is operable to determinean uplink scheduling timing l based on a configured TDD uplink/downlinkconfiguration. The transmitting module is operable to transmit, in a TTIn+l, an uplink transmission in accordance with the uplink grant receivedin the TTI n. The uplink scheduling timing l is a number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or 3.

Embodiments of a method of operation of a radio access node in acellular communications network are also disclosed. In some embodiments,a method of operation of a radio access node in a cellularcommunications network comprises transmitting an uplink grant to awireless device in a TTI n and receiving, in a TTI n+l, an uplinktransmission from the wireless device in accordance with the uplinkgrant transmitted to the wireless device in the TTI n, where l is anuplink scheduling timing l and is a function of a configured TDDuplink/downlink configuration. The uplink scheduling timing l is anumber of TTIs that is larger than or equal to a predefined minimumuplink scheduling timing value such that n+l is an uplink TTI and thepredefined minimum uplink scheduling timing value is 2 or 3.

In some embodiments, the uplink scheduling timing l is a smallestinteger number of TTIs that is larger than or equal to a predefinedminimum uplink scheduling timing value such that n+l is an uplink TTIand the predefined minimum uplink scheduling timing value is 2 or 3.

In some embodiments, the uplink grant schedules multiple uplink TTIs forthe same wireless device.

In some embodiments, the uplink grant comprises an indication of one ormore uplink TTIs for which the uplink grant is valid.

In some embodiments, an uplink part of special SFs can be used foruplink data transmission, and the uplink scheduling timing l isdetermined in such a manner that the uplink part of the special SFs aretreated as uplink TTIs. In some other embodiments, the uplink schedulingtiming l is determined in such a manner that the uplink part of thespecial SFs are not treated as uplink TTIs.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 1, and the uplink schedulingtiming l is 3 if n=0, the uplink scheduling timing l is 5 if n=1, theuplink scheduling timing l is 3 if n=4, the uplink scheduling timing lis 3 if n=5, the uplink scheduling timing l is 5 if n=6, and the uplinkscheduling timing l is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 2, and the uplink schedulingtiming l is 3 if n=3, the uplink scheduling timing l is 3 if n=4, theuplink scheduling timing l is 3 if n=8, and the uplink scheduling timingl is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 3, and the uplink schedulingtiming l is 3 if n=0, the uplink scheduling timing l is 3 if n=1, theuplink scheduling timing l is 3 if n=8, and the uplink scheduling timingl is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 4, and the uplink schedulingtiming l is 3 if n=0, the uplink scheduling timing l is 3 if n=8, andthe uplink scheduling timing l is 3 if n=9.

In some embodiments, the configured TDD uplink/downlink configuration isLTE TDD uplink/downlink configuration 5, and the uplink schedulingtiming l is 3 if n=8 and the uplink scheduling timing l is 3 if n=9.

In some embodiments, the uplink scheduling timing l is determined basedon the configured TDD uplink/downlink configuration and a UI comprisedin the uplink grant in the TTI n.

In some embodiments, the TTI n and the TTI n+l are 1 ms TTIs.

Embodiments of a radio access node for a cellular communications networkare also disclosed. In some embodiments, a radio access node for acellular communications network is adapted to transmit an uplink grantto a wireless device in a TTI n and receive, in a TTI n+l, an uplinktransmission from the wireless device in accordance with the uplinkgrant transmitted to the wireless device in the TTI n, where l is anuplink scheduling timing and is a function of a configured TDDuplink/downlink configuration. The uplink scheduling timing l is asmallest integer number of TTIs that is larger than or equal to apredefined minimum uplink scheduling timing value such that n+l is anuplink TTI and the predefined minimum uplink scheduling timing value is2 or 3.

In some embodiments, the radio access node is further adapted to performthe method of operation of a radio access node according to any otherembodiments of the method of operation of a radio access node disclosedherein.

In some embodiments, a radio access node for a cellular communicationsnetwork comprises at least one transmitter and at least one receiver, atleast one processor, and memory comprising instructions executable bythe at least one processor whereby the radio access node is operable totransmit an uplink grant to a wireless device in a TTI n and receive, ina TTI n+l, an uplink transmission from the wireless device in accordancewith the uplink grant transmitted to the wireless device in the TTI n,where l is an uplink scheduling timing and is a function of a configuredTDD uplink/downlink configuration. The uplink scheduling timing l is asmallest integer number of TTIs that is larger than or equal to apredefined minimum uplink scheduling timing value such that n+l is anuplink TTI and the predefined minimum uplink scheduling timing value is2 or 3.

In some embodiments, a radio access node for a cellular communicationsnetwork comprises a transmitting module and a receiving module. Thetransmitting module is operable to transmit an uplink grant to awireless device in a TTI n. The receiving module is operable to receive,in a TTI n+l, an uplink transmission from the wireless device inaccordance with the uplink grant transmitted to the wireless device inthe TTI n, where l is an uplink scheduling timing and is a function of aconfigured TDD uplink/downlink configuration. The uplink schedulingtiming l is a smallest integer number of TTIs that is larger than orequal to a predefined minimum uplink scheduling timing value such thatn+l is an uplink TTI and the predefined minimum uplink scheduling timingvalue is 2 or 3.

Other embodiments of a method of operation of a wireless device in acellular communications network are also disclosed. In some embodiments,a method of operation of a wireless device in a cellular communicationsnetwork comprises receiving an uplink grant in a TTI n, determining anuplink scheduling timing l based on a configured TDD uplink/downlinkconfiguration where the uplink scheduling timing l is a number of TTIsthat is larger than or equal to a predefined minimum uplink schedulingtiming value such that n+l is an uplink TTI, and transmitting, in a TTIn+l, an uplink transmission in accordance with the uplink grant receivedin the TTI n. An uplink part of special SFs can be used for uplink datatransmission, and determining the uplink scheduling timing l comprisesdetermining the uplink scheduling timing l in such a manner that theuplink part of the special SFs are treated as uplink TTIs.

In some embodiments, the predefined minimum uplink scheduling timingvalue is 2, 3, or 4. Further, in some embodiments, the uplink schedulingtiming l is a smallest integer number of TTIs that is larger than orequal to the predefined minimum uplink scheduling timing value such thatn+l is an uplink TTI.

In some embodiments, the uplink grant schedules multiple uplink TTIs forthe same wireless device.

In some embodiments, the uplink grant comprises an indication of one ormore uplink TTIs for which the uplink grant is valid.

In some embodiments, determining the uplink scheduling timing lcomprises determining the uplink scheduling timing l based on theconfigured TDD uplink/downlink configuration and a UI comprised in theuplink grant received in the TTI n.

In some embodiments, the TTI n and the TTI n+l are 1 ms TTIs.

Other embodiments of a wireless device for a cellular communicationsnetwork are also disclosed. In some embodiments, a wireless device for acellular communications network is adapted to receive an uplink grant ina TTI n, determine an uplink scheduling timing l based on a configuredTDD uplink/downlink configuration where the uplink scheduling timing lis a number of TTIs that is larger than or equal to a predefined minimumuplink scheduling timing value such that n+l is an uplink TTI, andtransmit, in a TTI n+l, an uplink transmission in accordance with theuplink grant received in the TTI n. An uplink part of special SFs can beused for uplink data transmission, and the wireless device determinesthe uplink scheduling timing l in such a manner that the uplink part ofthe special SFs are treated as uplink TTIs.

In some embodiments, the wireless device is further adapted to performthe method of operation of a wireless device according to any otherembodiments of the method of operation of a wireless device disclosedherein.

In some embodiments, a wireless device for a cellular communicationsnetwork comprises at least one transceiver, at least one processor, andmemory comprising instructions executable by the at least one processorwhereby the wireless device is operable to receive an uplink grant in aTTI n, determine an uplink scheduling timing l based on a configured TDDuplink/downlink configuration where the uplink scheduling timing l is anumber of TTIs that is larger than or equal to a predefined minimumuplink scheduling timing value such that n+l is an uplink TTI, andtransmit, in a TTI n+l, an uplink transmission in accordance with theuplink grant received in the TTI n. An uplink part of special SFs can beused for uplink data transmission, and the wireless device is operableto determine the uplink scheduling timing l in such a manner that theuplink part of the special SFs are treated as uplink TTIs.

In some embodiments, a wireless device for a cellular communicationsnetwork comprises a receiving module, a determining module, and atransmitting module. The receiving module is operable to receive anuplink grant in a TTI n. The determining module is operable to determinean uplink scheduling timing l based on a configured TDD uplink/downlinkconfiguration, the uplink scheduling timing l being a number of TTIsthat is larger than or equal to a predefined minimum uplink schedulingtiming value such that n+l is an uplink TTI. The transmitting module isoperable to transmit, in a TTI n+l, an uplink transmission in accordancewith the uplink grant received in the TTI n. An uplink part of specialSFs can be used for uplink data transmission, and the wireless devicedetermines the uplink scheduling timing l in such a manner that theuplink part of the special SFs are treated as uplink TTIs.

Other embodiments of method of operation of a radio access node in acellular communications network are also disclosed. In some embodiments,a method of operation of a radio access node in a cellularcommunications network comprises transmitting an uplink grant to awireless device in a TTI n and receiving, in a TTI n+l, an uplinktransmission from the wireless device in accordance with the uplinkgrant transmitted to the wireless device in the TTI n, where l is anuplink scheduling timing and the uplink scheduling timing l is a numberof TTIs that is larger than or equal to a predefined minimum uplinkscheduling timing value such that n+l is an uplink TTI. An uplink partof special SFs can be used for uplink data transmission, and the uplinkscheduling timing l is determined in such a manner that the uplink partof the special SFs are treated as uplink TTIs.

In some embodiments, the predefined minimum uplink scheduling timingvalue is 2, 3, or 4. Further, in some embodiments, the uplink schedulingtiming l is a smallest integer number of TTIs that is larger than orequal to the predefined minimum uplink scheduling timing value such thatn+l is an uplink TTI.

In some embodiments, the uplink grant schedules multiple uplink TTIs forthe same wireless device.

In some embodiments, the uplink grant comprises an indication of one ormore uplink TTIs for which the uplink grant is valid.

In some embodiments, the uplink scheduling timing l is determined basedon a configured TDD uplink/downlink configuration and a UI comprised inthe uplink grant in the TTI n.

In some embodiments, the TTI n and the TTI n+l are 1 ms TTIs.

Other embodiments of a radio access node for a cellular communicationsnetwork are also disclosed. In some embodiments, a radio access node fora cellular communications network is adapted to transmit an uplink grantto a wireless device in a TTI n and receive, in a TTI n+l, an uplinktransmission from the wireless device in accordance with the uplinkgrant transmitted to the wireless device in the TTI n, where l is anuplink scheduling timing and the uplink scheduling timing l is a numberof TTIs that is larger than or equal to a predefined minimum uplinkscheduling timing value such that n+l is an uplink TTI and is a functionof a configured TDD uplink/downlink configuration. An uplink part ofspecial SFs can be used for uplink data transmission, and the uplinkscheduling timing l is determined in such a manner that the uplink partof the special SFs are treated as uplink TTIs.

In some embodiments, the radio access node is further adapted to performthe method of operation of a radio access node according to any otherembodiments of the method of operation of a radio access node disclosedherein.

In some embodiments, a radio access node for a cellular communicationsnetwork comprises at least one transmitter and at least one receiver, atleast one processor, and memory comprising instructions executable bythe at least one processor whereby the radio access node is operable totransmit an uplink grant to a wireless device in a TTI n and receive, ina TTI n+l, an uplink transmission from the wireless device in accordancewith the uplink grant transmitted to the wireless device in the TTI n,where l is an uplink scheduling timing and the uplink scheduling timingl is a number of TTIs that is larger than or equal to a predefinedminimum uplink scheduling timing value such that n+l is an uplink TTIand is a function of a configured TDD uplink/downlink configuration. Anuplink part of special SFs can be used for uplink data transmission, andthe uplink scheduling timing l is determined in such a manner that theuplink part of the special SFs are treated as uplink TTIs.

In some embodiments, a radio access node for a cellular communicationsnetwork comprises a transmitting module and a receiving module. Thetransmitting module is operable to transmit an uplink grant to awireless device in a TTI n. The receiving module is operable to receive,in a TTI n+l, an uplink transmission from the wireless device inaccordance with the uplink grant transmitted to the wireless device inthe TTI n, where l is an uplink scheduling timing and the uplinkscheduling timing l is a number of TTIs that is larger than or equal toa predefined minimum uplink scheduling timing value such that n+l is anuplink TTI and is a function of a configured TDD uplink/downlinkconfiguration. An uplink part of special SFs can be used for uplink datatransmission, and the uplink scheduling timing l is determined in such amanner that the uplink part of the special SFs are treated as uplinkTTIs.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIG. 1 illustrates one example of a cellular communications network inwhich embodiments of the present disclosure may be implemented;

FIG. 2 illustrates the operation of the radio access node and thewireless device of FIG. 1 according to some embodiments of the presentdisclosure;

FIGS. 3 through 5 illustrate scheduling timing for Time DivisionDuplexing (TDD) uplink/downlink configuration 0 according to someembodiments of the present disclosure;

FIGS. 6 through 8 illustrate scheduling timing for TDD uplink/downlinkconfiguration 1 according to some embodiments of the present disclosure;

FIGS. 9 and 10 illustrate scheduling timing for TDD uplink/downlinkconfiguration 2 according to some embodiments of the present disclosure;

FIGS. 11 through 14 illustrate scheduling timing for TDD uplink/downlinkconfiguration 3 according to some embodiments of the present disclosure;

FIGS. 15 and 16 illustrate scheduling timing for TDD uplink/downlinkconfiguration 4 according to some embodiments of the present disclosure;

FIGS. 17 and 18 illustrate scheduling timing for TDD uplink/downlinkconfiguration 5 according to some embodiments of the present disclosure;

FIGS. 19 through 23 illustrate scheduling timing for TDD uplink/downlinkconfiguration 6 according to some embodiments of the present disclosure;

FIGS. 24 through 26 illustrate embodiments of a radio access node; and

FIGS. 27 and 28 illustrate embodiments of a wireless device.

DETAILED DESCRIPTION

The embodiments set forth below represent information to enable thoseskilled in the art to practice the embodiments and illustrate the bestmode of practicing the embodiments. Upon reading the followingdescription in light of the accompanying drawing figures, those skilledin the art will understand the concepts of the disclosure and willrecognize applications of these concepts not particularly addressedherein. It should be understood that these concepts and applicationsfall within the scope of the disclosure and the accompanying claims.

Radio Node: As used herein, a “radio node” is either a radio access nodeor a wireless device.

Radio Access Node: As used herein, a “radio access node” is any node ina radio access network of a cellular communications network thatoperates to wirelessly transmit and/or receive signals. Some examples ofa radio access node include, but are not limited to, a base station(e.g., an enhanced or evolved Node B (eNB) in a Third GenerationPartnership Project (3GPP) Long Term Evolution (LTE) network), ahigh-power or macro base station, a low-power base station (e.g., amicro base station, a pico base station, a home eNB, or the like), and arelay node.

Core Network Node: As used herein, a “core network node” is any type ofnode in a Core Network (CN). Some examples of a core network nodeinclude, e.g., a Mobility Management Entity (MME), a Packet Data Network(PDN) Gateway (P-GW), a Service Capability Exposure Function (SCEF), orthe like.

Wireless Device: As used herein, a “wireless device” is any type ofdevice that has access to (i.e., is served by) a cellular communicationsnetwork by wirelessly transmitting and/or receiving signals to a radioaccess node(s). Some examples of a wireless device include, but are notlimited to, a User Equipment device (UE) in a 3GPP network and a MachineType Communication (MTC) device.

Network Node: As used herein, a “network node” is any node that iseither part of the radio access network or the CN of a cellularcommunications network/system.

Note that the description given herein focuses on a 3GPP cellularcommunications system and, as such, 3GPP LTE terminology or terminologysimilar to 3GPP LTE terminology is oftentimes used. However, theconcepts disclosed herein are not limited to LTE or a 3GPP system.

Note that, in the description herein, reference may be made to the term“cell;” however, particularly with respect to Fifth Generation (5G)concepts, beams may be used instead of cells and, as such, it isimportant to note that the concepts described herein are equallyapplicable to both cells and beams.

For LTE Release 15, it has been agreed to reduce processing time toallow for shorter latency. UE capabilities have improved and a fasterprocessing time can be expected nowadays compared to what could be donein the first release of LTE. With reduced processing time, the inventorsenvision that the downlink Hybrid Automatic Repeat Request (HARQ) timingwill be chosen between n+2 or n+3. Similarly with reduced processingtime, the inventors envision that the uplink scheduling timing (uplinkgrant to uplink data delay) will be chosen between n+2 or n+3. Thetables in the LTE specifications that give the uplink scheduling timingfor Time Division Duplexing (TDD) do not capture the processing timereduction for uplink grant to uplink data. These tables need to bemodified to achieve lower latency.

Moreover, by introducing data transmission in Uplink Part of a SpecialSubframe (UpPTS), it becomes possible to transmit Physical Uplink SharedChannel (PUSCH) within the special Subframes (SFs). This implies thatuplink scheduling timing needs to be defined for uplink transmissionsoccurring in UpPTS.

Two different methods, i.e., latency optimized and load balancing, areproposed for the design of new Uplink Index (UI) scheduling timingtables for supporting reduced processing time with 1 millisecond (ms)Transmission Time Interval (TTI) operations in TDD.

For the latency optimized approach, the uplink scheduling grant sent inTTI n is valid for TTI n+l, where l is the smallest value larger than orequal to a predefined minimum timing (e.g., 2 or 3 ms) such that n+l isan uplink TTI.

For the load balancing approach, the uplink scheduling assignments areequally distributed over different downlink TTIs.

Methods for designing uplink scheduling timing with uplink datatransmission on UpPTS are proposed.

The proposed solution provides new uplink scheduling timing tables toenable reduced processing time with 1 ms TTI in TDD. The latencyoptimized solution can offer the largest latency reduction gain. On theother hand, the load balancing based solution can simplify the controldesign, with reduced control signaling overhead.

FIG. 1 illustrates one example of a cellular communications network 10in which embodiments of the present disclosure may be implemented. Asillustrated, the cellular communications network 10 includes a radioaccess node 12 (e.g., a base station or eNB) and a wireless device 14.In the embodiments described herein, the radio access node 12 and thewireless device 14 operate according to a TDD scheme in which some SFsare downlink SFs, some SFs are uplink SFs, and some SFs are special SFs.Embodiments of the present disclosure relate to uplink scheduling timingfor 1 ms TTI operations in TDD.

Two different methods, i.e., latency optimized and load balancing, areproposed for the design of a new uplink scheduling timing table forsupporting reduced processing time with 1 ms TTI operations in TDD.

It is further understood that the timing designs can be extended tosupport Carrier Aggregation (CA) with both Frequency Division Duplexing(FDD) and TDD carriers, among different TDD carriers and also amongFrame Structure (FS) type 3 (FS3) carriers and TDD carriers. The timingrelations that will be used are formed from the design provided in thepresent disclosure and extends the CA design.

In one embodiment, the timing relations are designed based on thelatency optimized approach; that is, the uplink scheduling grant sent inTTI n is valid for TTI n+l, where l is the smallest value larger than orequal to a predefined minimum timing such that n+l is an uplink TTI. Asdescribed herein, the predefined minimum timing is 2 in some embodimentsand 3 in some other embodiments.

In another embodiment, the timing relations are designed based on theload balancing approach; that is, the uplink scheduling assignments areequally distributed over different downlink TTIs.

In one embodiment, the timing relations for different downlink/uplinkconfigurations are designed based on different approaches, i.e., somedownlink/uplink configurations are designed based on the latencyoptimization approach while the other downlink/uplink configurations aredesigned based on the load balancing approach.

In one embodiment, if multiple uplink TTIs need to be scheduled in onedownlink TTI, then the same UE is scheduled on all these uplink TTIsbased on the same uplink Downlink Control Information (DCI), such thatonly one uplink scheduling grant needs to be sent from the downlink TTI.

In another embodiment, if multiple uplink TTIs need to be scheduled inone downlink TTI, then a field in the uplink DCI, e.g., a UI field, isused to signal for which uplink TTI(s) the grant is valid. If a loadbalancing approach is adopted to spread out the uplink grants, it candone so to consider to limit the number of bits in the uplink field,e.g. to 2 bits.

In one embodiment, UpPTS of the special SFs can be used for uplink datatransmission, and the uplink scheduling timing for all uplink TTItransmissions are designed based on either the latency optimizedapproach or the load balancing approach, by treating UpPTS as an uplinkTTI, i.e., by taking the scheduling of uplink data transmission in UpPTSinto account.

In another embodiment, UpPTS of the special SFs can be used for uplinkdata transmission, and the uplink scheduling timing for all uplink TTItransmissions within legacy uplink SFs are firstly designed based oneither the latency optimized approach or the load balancing approach, bynot taking scheduling of data transmission in UpPTS into account; then,the uplink scheduling timing for data transmission in TTI(s), whichconsist(s) of UpPTS, is added on top of the latency optimized approachor the load balancing approach.

In this regard, FIG. 2 illustrates the operation of the radio accessnode 12 and the wireless device 14 according to some embodiments of thepresent disclosure. As illustrated, the radio access node 12 transmits(e.g., broadcasts) an uplink/downlink (UL/DL) configuration (step 100).At some point, the radio access node 12 transmits an uplink grant to thewireless device 14 in TTI n (step 102). Based on the uplink/downlinkconfiguration and the value of n, the wireless device 14 determines anuplink timing l for transmitting an uplink transmission to the radioaccess node 12 in accordance with the uplink grant (step 104). Asdescribed herein, the uplink timing l is an integer value larger than orequal to a predefined minimum timing such that TTI n+l is an uplink TTI.In some embodiments, the predefined minimum timing is 2. In some otherembodiments, the predefined minimum timing is 3. In some otherembodiments, the predefined minimum timing is 4.

As described herein, in some embodiments, the UpPTS can be used foruplink data transmission, and the wireless device 14 determines theuplink scheduling timing l in such a manner that the UpPTSs are treatedas uplink TTIs. Further, in some embodiments, the predefined minimumtiming is 2, 3, or 4, depending on the particular embodiment.

As also described herein, in some other embodiments, the UpPTS cannot beused for uplink data transmission, and the wireless device 14 determinesthe uplink scheduling timing l in such a manner that the UpPTSs are nottreated as uplink TTIs. Further, in some embodiments, the predefinedminimum timing is 2 or 3, depending on the particular embodiment.

As discussed herein, in some embodiments, the wireless device 14determines the uplink timing l based on predefined tables (e.g., tablesspecified in a standard). As an example, the uplink timing l may bedetermined using the tables defined below. In some embodiments, theuplink timing l is defined in accordance with a latency optimizationapproach. For the latency optimized approach, the uplink timing l is thesmallest value larger than or equal to a predefined minimum timing suchthat TTI n+l is an uplink TTI. In other embodiments, the uplink timing lis defined in accordance with a load balancing approach. Notably, asdiscussed above, in some embodiments, if multiple uplink TTIs need to bescheduled in one downlink TTI, then the same wireless device 12 isscheduled on all of these uplink TTIs, e.g., based on the same uplinkDCI such that only one uplink scheduling grant is sent in the downlinkTTI. In other embodiments, if multiple uplink TTIs need to be scheduledin one downlink TTI, then a field in the uplink DCI, e.g., a UI field,is used to signal for which uplink TTI(s) the grant is valid. If a loadbalancing approach is adopted to spread out the uplink grants, it candone so to consider to limit the number of bits in the uplink field,e.g. to 2 bits. Further, in some embodiments, the uplink timing l isdetermined (e.g., the predefined tables are defined) such that the UpPTSof the special SFs are treated as uplink TTIs. In a similar manner, theradio access node 12 knows the uplink timing l such that the radioaccess node 12 knows when to expect the respective uplink transmissionfrom the wireless device 14. The wireless device 14 transmits, and theradio access node 12 receives, the uplink transmission in TTI n+l (step106).

In the following, deriving the uplink scheduling timing tables forreduced processing time and 1 ms TTI for different downlink/uplinkconfigurations is shown. The uplink scheduling grant sent in TTI n isvalid for TTI n+l, where l is the smallest value larger than or equal toa predefined minimum uplink timing (k₀) such that n+l is an uplink TTI.In the following the uplink scheduling timing for different k₀ aregiven. In certain cases, only the uplink scheduling timing for k₀=3 isgiven but the same methodology can be applied for other values of k₀.

FIGS. 3 to 5 show the scheduling timing for TDD uplink/downlinkconfiguration 0 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach. Since there are more uplink SFs to schedule thanthere are downlink SFs for sending the uplink grant, a downlink SF needsto schedule multiple uplink SFs. This can be done by including a fieldwith, for instance, two bits in the uplink grant that would indicatewhich uplink SFs are scheduled from the same uplink grant/downlink SF.The existing uplink index in the uplink grant can be used for thatpurpose in this case too. Another solution for handling this multi-UEscheduling issue is to schedule the same UE to all these multiple uplinkSFs by using the same uplink DCI.

FIGS. 3 to 5 show the case where the UI is 10 and 01 in the uplinkgrant. In the case where the UI is set to 11, the two uplink SFsindicated separately with 10 and 01 are scheduled. An example based onFIG. 3: if the uplink grant in the first downlink SF contains a field UIset to 11, both the uplink SFs 3 and 4 are scheduled.

FIGS. 6 to 8 show the scheduling timing for TDD uplink/downlinkconfiguration 1 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach in case of k₀=2 or 3 ms.

In case of PUSCH in UpPTS and k₀=4 ms, the latency-optimized approachleads to the situation where a downlink SF (or Downlink Part of aSpecial Subframe (DwPTS) of the special SF) contains the uplink grantfor both UpPTS and the next uplink SF. This means that the downlink SFcontains a field with two bits (similar to the UI mentioned earlier) inthe uplink grant to indicate which uplink SF(s) is scheduled. The loadbalancing approach or the case of PUSCH in UpPTS and k₀=4 ms does notlead to this situation but the average delay between the uplink grant touplink data is increased by 7% compared to the latency-optimizedapproach. Considering this small difference in the delay, the loadbalancing approach appears more attractive for this configuration.

Another solution for handling the multi-UE scheduling issue when usingthe latency-optimized approach is to schedule the same UE to all thesemultiple uplink SFs by using the same uplink DCI.

FIGS. 9 and 10 show the scheduling timing for TDD uplink/downlinkconfiguration 2 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach.

FIGS. 11 to 14 show the scheduling timing for TDD uplink/downlinkconfiguration 3 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach in case of k₀=4 or 3 ms.

In case of PUSCH in UpPTS and k₀=2 ms, the latency-optimized approachleads to the situation where a downlink SF (or downlink part of thespecial SF) contains the uplink grant for two uplink SFs (see FIG. 12and FIG. 14). This means that the downlink SF contains a field with twobits (similar to the UI mentioned earlier) in the uplink grant toindicate which uplink SF(s) is scheduled. The load balancing approach orthe case of PUSCH in UpPTS and k₀=4 ms does not lead to this situationbut the average delay between the uplink grant to uplink data is longercompared to the latency-optimized approach.

FIGS. 15 and 16 show the scheduling timing for TDD uplink/downlinkconfiguration 4 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach.

FIGS. 17 and 18 show the scheduling timing for TDD uplink/downlinkconfiguration 5 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach.

FIGS. 19 to 23 show the scheduling timing for TDD uplink/downlinkconfiguration 6 with and without PUSCH in UpPTS. The uplink schedulingtiming is the same for the latency optimized approach and the loadbalancing approach in case of k₀=4 and PUSCH in UpPTS.

In case of no PUSCH in UpPTS and k₀=2 or 3 ms, the latency-optimizedapproach leads to the situation where a downlink SF (or downlink part ofthe special SF) contains the uplink grant for two uplink SFs (see FIG.19). This means that the uplink grant sent in the downlink SFs containsa field with two bits (similar to the UI mentioned earlier) to indicatewhich uplink SF(s) is scheduled. The load balancing approach does notlead to this situation but the average delay between the uplink grant touplink data is increased by 28% compared to the latency-optimizedapproach. In that case the latency-optimized approach appears moreattractive at the cost of some higher control payload (two additionalbits in the uplink grant or separate uplink grants). Another solutionfor handling this multi-UE scheduling issue is to schedule the same UEto all these multiple uplink SFs by using the same uplink DCI.

In case of PUSCH in UpPTS and k₀=2 or 3 ms, the multi-uplink schedulingissue cannot be avoided even with the load balancing approach. In thiscase, a field similar to UI must be used to indicate the scheduleduplink SF(s), unless these uplink SFs are scheduled to the same UE byusing the same DCI.

In the following description, the uplink scheduling timing for differentdownlink/uplink configurations are summarized into tables. Note that,for all examples shown in this section, it is assumed that the minimumuplink scheduling timing is three times of the TTI length (k₀=3). Thetables will look different when the minimum timing is different.However, in that case the tables can be created from the figures in theprevious section that cover k₀=2 or k₀=4.

Assuming that UpPTS does not contain PUSCH, Tables 6 and 7 give thecorresponding uplink scheduling timing for 1 ms TTI and k₀=3.

For TDD uplink/downlink configurations 1-6, the UE shall, upon detectionof a Physical Downlink Control Channel (PDCCH)/Enhanced PDCCH (EPDCCH)with uplink DCI format in SF n intended for the UE, adjust thecorresponding PUSCH transmission in SF n+k, with k given in Table 6 ifthe latency-optimized approach is chosen or Table 7 if the loadbalancing approach is chosen.

For TDD uplink/downlink configuration 0 the UE shall adjust thecorresponding PUSCH transmission in SF n+k if the first bit of the UI inthe uplink grant is set to 1 with k given in Table 6 if thelatency-optimized approach is chosen or Table 7 if the load balancingapproach is chosen. If the second bit of the UI in the uplink grant isset to 1 in SF n, the UE shall adjust the corresponding PUSCHtransmission in SF n+3. If the UI in the uplink grant sent in SF n isset to 11, the UE shall adjust the corresponding PUSCH transmission inboth SFs n+k and n+3, with k given in Table 6 if the latency-optimizedapproach is chosen or Table 7 if the load balancing approach is chosen.Note that the exact same behaviour can be achieved by swapping the roleof the first bit of the UI and the role of the second bit.

TABLE 6 Uplink Scheduling Timing for TDD with 1 ms TTI and ReducedProcessing Time k₀ = 3 (Latency Optimized, No PUSCH in UpPTS) TDD UL/DLsubframe number n Configuration 0 1 2 3 4 5 6 7 8 9 0 4 6 4 6 1 3 3 3 32 3 3 3 3 3 3 4 3 3 5 3 6 3 3, 6 3 3

TABLE 7 Uplink Scheduling Timing for TDD with 1 ms TTI and ReducedProcessing Time k₀ = 3 (Load Balancing Approach, No PUSCH in UpPTS) TDDUL/DL subframe number n Configuration 0 1 2 3 4 5 6 7 8 9 0 4 6 4 6 1 33 3 3 2 3 3 3 3 3 3 4 3 3 5 3 6 4 6 3 6 4

Assuming that UpPTS contains PUSCH, Table 8 and Table 9 give thecorresponding uplink scheduling timing for 1 ms TTI and k₀=3.

The UE shall upon detection of a PDCCH/EPDCCH with uplink DCI format inSF n intended for the UE, adjust the corresponding PUSCH transmission inSF n+k, with k given in Table 8 if the latency-optimized approach ischosen or Table 9 if the load balancing approach is chosen.

For configuration 0 and 6, a field is added in the uplink DCI toindicate which of the multiple possible SFs is scheduled to the UE.

TABLE 8 Uplink Scheduling Timing for TDD with 1 ms TTI and ReducedProcessing Time k₀ = 3 (Latency Optimized, PUSCH in UpPTS) TDD UL/DLsubframe number n Configuration 0 1 2 3 4 5 6 7 8 9 0 3, 6 3, 6 3, 6 3,6 1 3 5 3 3 5 3 2 3 3 3 3 3 3 3 3 3 4 3 3 3 5 3 3 6 3 3, 5, 3 5 3 6

TABLE 9 Uplink Scheduling Timing for TDD with 1 ms TTI and ReducedProcessing Time k₀ = 3 (Load Balancing Approach, PUSCH in UpPTS) TDDUL/DL subframe number n Configuration 0 1 2 3 4 5 6 7 8 9 0 3, 6 3, 6 3,6 3, 6 1 3 5 3 3 5 3 2 3 3 3 3 3 3 3 3 3 4 3 3 3 5 3 3 6 3, 4 5, 6 3 5 3

Two different methods, i.e., latency optimized and load balancing, areproposed for the design of new uplink scheduling timing tables forsupporting 1 ms TTI operations with reduced processing time in TDD.

FIG. 24 is a schematic block diagram of the radio access node 12according to some embodiments of the present disclosure. As illustrated,the radio access node 12 includes a control system 16 that includes oneor more processors 18 (e.g., Central Processing Units (CPUs),Application Specific Integrated Circuits (ASICs), Field ProgrammableGate Arrays (FPGAs), and/or the like), memory 20, and a networkinterface 22. In addition, the radio access node 12 includes one or moreradio units 24 that each includes one or more transmitters 26 and one ormore receivers 28 coupled to one or more antennas 30. In someembodiments, the radio unit(s) 24 is external to the control system 16and connected to the control system 16 via, e.g., a wired connection(e.g., an optical cable). However, in some other embodiments, the radiounit(s) 24 and potentially the antenna(s) 30 are integrated togetherwith the control system 16. The one or more processors 18 operate toprovide one or more functions of a radio access node 12 as describedherein. In some embodiments, the function(s) are implemented in softwarethat is stored, e.g., in the memory 20 and executed by the one or moreprocessors 18.

FIG. 25 is a schematic block diagram that illustrates a virtualizedembodiment of the radio access node 12 according to some embodiments ofthe present disclosure. This discussion is equally applicable to othertypes of network nodes. Further, other types of network nodes may havesimilar virtualized architectures.

As used herein, a “virtualized” radio access node 12 is animplementation of the radio access node 12 in which at least a portionof the functionality of the radio access node 12 is implemented as avirtual component(s) (e.g., via a virtual machine(s) executing on aphysical processing node(s) in a network(s)). As illustrated, in thisexample, the radio access node 12 includes the control system 16(optional) that includes the one or more processors 18 (e.g., CPUs,ASICs, FPGAs, and/or the like), the memory 20, and the network interface22 and the one or more radio units 24 that each includes the one or moretransmitters 26 and the one or more receivers 28 coupled to the one ormore antennas 30, as described above. The control system 16 is connectedto the radio unit(s) 24 via, for example, an optical cable or the like.The control system 16 is connected to one or more processing nodes 32coupled to or included as part of a network(s) 34 via the networkinterface 22. Each processing node 32 includes one or more processors 36(e.g., CPUs, ASICs, FPGAs, and/or the like), memory 38, and a networkinterface 40.

In this example, functions 42 of the radio access node 12 describedherein are implemented at the one or more processing nodes 32 ordistributed across the control system 16 and the one or more processingnodes 32 in any desired manner. In some particular embodiments, some orall of the functions 42 of the radio access node 12 described herein areimplemented as virtual components executed by one or more virtualmachines implemented in a virtual environment(s) hosted by theprocessing node(s) 32. As will be appreciated by one of ordinary skillin the art, additional signaling or communication between the processingnode(s) 32 and the control system 16 is used in order to carry out atleast some of the desired functions 42. Notably, in some embodiments,the control system 16 may not be included, in which case the radiounit(s) 24 communicate directly with the processing node(s) 32 via anappropriate network interface(s).

In some embodiments, a computer program including instructions which,when executed by at least one processor, causes the at least oneprocessor to carry out the functionality of a radio access node 12 or anode (e.g., a processing node 32) implementing one or more of thefunctions 42 of the radio access node 12 in a virtual environmentaccording to any of the embodiments described herein is provided. Insome embodiments, a carrier comprising the aforementioned computerprogram product is provided. The carrier is one of an electronic signal,an optical signal, a radio signal, or a computer readable storage medium(e.g., a non-transitory computer readable medium such as memory).

FIG. 26 is a schematic block diagram of the radio access node 12according to some other embodiments of the present disclosure. The radioaccess node 12 includes one or more modules 44, each of which isimplemented in software. The module(s) 44 provide the functionality ofthe radio access node 12 described herein. This discussion is equallyapplicable to the processing node 32 of FIG. 25 where the modules 44 maybe implemented at one of the processing nodes 32 or distributed acrossmultiple processing nodes 32 and/or distributed across the processingnode(s) 32 and the control system 16.

FIG. 27 is a schematic block diagram of a wireless device 14 accordingto some embodiments of the present disclosure. As illustrated, thewireless device 14 includes one or more processors 46 (e.g., CPUs,ASICs, FPGAs, and/or the like), memory 48, and one or more transceivers50 each including one or more transmitters 52 and one or more receivers54 coupled to one or more antennas 56. In some embodiments, thefunctionality of the wireless device 14 described above may be fully orpartially implemented in software that is, e.g., stored in the memory 48and executed by the processor(s) 46.

In some embodiments, a computer program including instructions which,when executed by at least one processor, causes the at least oneprocessor to carry out the functionality of the wireless device 14according to any of the embodiments described herein is provided. Insome embodiments, a carrier comprising the aforementioned computerprogram product is provided. The carrier is one of an electronic signal,an optical signal, a radio signal, or a computer readable storage medium(e.g., a non-transitory computer readable medium such as memory).

FIG. 28 is a schematic block diagram of the wireless device 14 accordingto some other embodiments of the present disclosure. The wireless device14 includes one or more modules 58, each of which is implemented insoftware. The module(s) 58 provide the functionality of the wirelessdevice 14 described herein.

While not being limited thereto, some example embodiments of the presentdisclosure are provided below.

Embodiment 1

A method of operation of a wireless device (14) in a cellularcommunications network (10), comprising: receiving (102) an uplink grantin TTI n; determining (104), based on a configured uplink/downlinkconfiguration, an uplink scheduling timing l; and transmitting (106), ina TTI n+l, an uplink transmission in accordance with the uplink grantreceived in the TTI n.

Embodiment 2

The method of embodiment 1 wherein the uplink scheduling timing l is asmallest integer number of TTIs that is larger than or equal to apredefined minimum uplink scheduling timing value such that n+l is anuplink TTI.

Embodiment 3

The method of embodiments 1 wherein the uplink scheduling timing l isdefined based on a load balancing approach in which uplink schedulinggrants are equally distributed over different downlink TTIs.

Embodiment 4

The method of any one of embodiments 1 to 3 wherein the uplink grantschedules multiple uplink TTIs for the same wireless device (14).

Embodiment 5

The method of embodiment 4 wherein the uplink grant comprises anindication of one or more uplink TTIs for which the uplink grant isvalid.

Embodiment 6

The method of any one of embodiments 1 to 5 wherein an uplink part ofspecial SFs can be used for uplink data transmission, and determining(104) the uplink scheduling timing l comprises determining (104) theuplink scheduling timing l in such a manner that the uplink part of thespecial SFs are treated as uplink TTIs.

Embodiment 7

The method of embodiment 1 or 2 wherein determining the uplinkscheduling timing l comprises determining (104) the uplink schedulingtiming l based on a predefined table that defines values of 1 fordifferent values of n for the TDD uplink/downlink configuration.

Embodiment 8

The method of embodiment 7 wherein the predefined table defines thevalues of 1 for the different values of n for the TDD uplink/downlinkconfiguration in such a manner that an uplink part of special SFs aretreated as uplink short TTIs.

Embodiment 9

The method of embodiment 7 wherein the predefined table defines thevalues of 1 for the different values of n for the TDD uplink/downlinkconfiguration in such a manner that an uplink part of special SFs arenot treated as uplink short TTIs.

Embodiment 10

The method of any one of embodiments 7 to 9 wherein the predefined tabledefines the values of 1 for the different values of n in accordance witha latency optimization scheme.

Embodiment 11

The method of any one of embodiments 7 to 9 wherein the predefined tabledefines the values of l for the different values of n in accordance witha load sharing scheme.

Embodiment 12

A wireless device (14) in a cellular communications network (10), thewireless device (14) adapted to: receive an uplink grant in TTI n;determine, based on a configured uplink/downlink configuration, anuplink scheduling timing l; and transmit, in a TTI n+l, an uplinktransmission in accordance with the uplink grant received in the shortTTI n.

Embodiment 13

The wireless device (14) of embodiment 12 wherein the wireless device(14) is further adapted to perform the method of any one of embodiments2 to 11.

Embodiment 14

A wireless device (14) in a cellular communications network (10),comprising at least one transceiver (50), at least one processor (46),and memory (48) comprising instructions executable by the at least oneprocessor (46) whereby the wireless device (14) is operable to: receivean uplink grant in TTI n; determine, based on a configureduplink/downlink configuration, an uplink scheduling timing l; andtransmit, in a TTI n+l, an uplink transmission in accordance with theuplink grant received in the TTI n.

Embodiment 15

A wireless device (14) in a cellular communications network (10), thewireless device (14) comprising: a receiving module (58) operable toreceive an uplink grant in TTI n; a determining module (58) operable todetermine, based on a configured uplink/downlink configuration, anuplink scheduling timing l; and a transmitting module (58) operable totransmit, in a TTI n+l, an uplink transmission in accordance with theuplink grant received in the TTI n.

Embodiment 16

A method of operation of a radio access node (12) in a cellularcommunications network (10), comprising: transmitting (102) an uplinkgrant to a wireless device (14) in a TTI n; and receiving (106), in aTTI n+I, an uplink transmission from the wireless device (14) inaccordance with the uplink grant transmitted to the wireless device (14)in the TTI n.

The following acronyms are used throughout this disclosure.

-   -   3GPP Third Generation Partnership Project    -   5G Fifth Generation    -   ASIC Application Specific Integrated Circuit    -   BLER Block Error Rate    -   CA Carrier Aggregation    -   CN Core Network    -   CPU Central Processing Unit    -   DCI Downlink Control Information    -   DwPTS Downlink Part of a Special Subframe    -   eNB Enhanced or Evolved Node B    -   EPDCCH Enhanced Physical Downlink Control Channel    -   FDD Frequency Division Duplexing    -   FPGA Field Programmable Gate Array    -   FS Frame Structure    -   GP Guard Period    -   HARQ Hybrid Automatic Repeat Request    -   HTTP Hypertext Transfer Protocol    -   LAA License Assisted Access    -   LTE Long Term Evolution    -   LSB Least Significant Bit    -   MME Mobility Management Entity    -   ms Millisecond    -   MSB Most Significant Bit    -   MTC Machine Type Communication    -   PDCCH Physical Downlink Control Channel    -   PDN Packet Data Network    -   P-GW Packet Data Network Gateway    -   PHICH Physical Hybrid Automatic Repeat Request Indicator Channel    -   PUSCH Physical Uplink Shared Channel    -   RAT Radio Access Technology    -   SCEF Service Capability Exposure Function    -   SF Subframe    -   SIB System Information Block    -   TCP Transmission Control Protocol    -   TDD Time Division Duplexing    -   TS Technical Specification    -   TTI Transmission Time Interval    -   UE User Equipment    -   UI Uplink Index    -   UpPTS Uplink Part of a Special Subframe

Those skilled in the art will recognize improvements and modificationsto the embodiments of the present disclosure. All such improvements andmodifications are considered within the scope of the concepts disclosedherein.

1. A method of operation of a wireless device in a cellularcommunications network, comprising: receiving an uplink grant in aTransmission Time Interval, TTI, n; determining an uplink schedulingtiming l based on a configured Time Division Duplexing, TDD,uplink/downlink configuration; and transmitting, in a TTI n+l, an uplinktransmission in accordance with the uplink grant received in the TTI n;wherein the uplink scheduling timing l is a number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 2. The method of claim 1 wherein theuplink scheduling timing l is a smallest integer number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 3. The method of claim 1 wherein theuplink grant schedules multiple uplink TTIs for the same wirelessdevice.
 4. The method of claim 1 wherein the uplink grant comprises anindication of one or more uplink TTIs for which the uplink grant isvalid.
 5. The method of claim 1 wherein an uplink part of specialsubframes can be used for uplink data transmission, and determining theuplink scheduling timing l comprises determining the uplink schedulingtiming l in such a manner that the uplink part of the special subframesare treated as uplink TTIs.
 6. The method of claim 1 wherein determiningthe uplink scheduling timing l comprises determining the uplinkscheduling timing l in such a manner that the uplink part of the specialsubframes are not treated as uplink TTIs. 7-15. (canceled)
 16. Awireless device for a cellular communications network, comprising: atleast one transceiver; at least one processor; and memory comprisinginstructions executable by the at least one processor whereby thewireless device is operable to: receive an uplink grant in aTransmission Time Interval, TTI, n; determine an uplink schedulingtiming l based on a configured Time Division Duplexing, TDD,uplink/downlink configuration; and transmit, in a TTI n+l, an uplinktransmission in accordance with the uplink grant received in the TTI n;wherein the uplink scheduling timing l is a number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 17. (canceled)
 18. A method ofoperation of a radio access node in a cellular communications network,comprising: transmitting an uplink grant to a wireless device in aTransmission Time Interval, TTI, n; and receiving, in a TTI n+l, anuplink transmission from the wireless device in accordance with theuplink grant transmitted to the wireless device in the TTI n, where l isan uplink scheduling timing l and is a function of a configured TimeDivision Duplexing, TDD, uplink/downlink configuration; wherein theuplink scheduling timing l is a number of TTIs that is larger than orequal to a predefined minimum uplink scheduling timing value such thatn+l is an uplink TTI and the predefined minimum uplink scheduling timingvalue is 2 or
 3. 19. The method of claim 18 wherein the uplinkscheduling timing l is a smallest integer number of TTIs that is largerthan or equal to a predefined minimum uplink scheduling timing valuesuch that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 20. The method of claim 18 whereinthe uplink grant schedules multiple uplink TTIs for the same wirelessdevice.
 21. The method of claim 18 wherein the uplink grant comprises anindication of one or more uplink TTIs for which the uplink grant isvalid.
 22. The method of claim 18 wherein an uplink part of specialsubframes can be used for uplink data transmission, and the uplinkscheduling timing l is determined in such a manner that the uplink partof the special subframes are treated as uplink TTIs.
 23. The method ofclaim 18 wherein the uplink scheduling timing l is determined in such amanner that the uplink part of the special subframes are not treated asuplink TTIs. 24-32. (canceled)
 33. A radio access node for a cellularcommunications network, comprising: at least one transmitter and atleast one receiver; at least one processor; and memory comprisinginstructions executable by the at least one processor whereby the radioaccess node is operable to: transmit an uplink grant to a wirelessdevice in a Transmission Time Interval, TTI, n; and receive, in a TTIn+l, an uplink transmission from the wireless device in accordance withthe uplink grant transmitted to the wireless device in the TTI n, wherel is an uplink scheduling timing and is a function of a configured TimeDivision Duplexing, TDD, uplink/downlink configuration; wherein theuplink scheduling timing l is a smallest integer number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 34-56. (canceled)
 57. The wirelessdevice of claim 16 wherein the uplink scheduling timing l is a smallestinteger number of TTIs that is larger than or equal to a predefinedminimum uplink scheduling timing value such that n+l is an uplink TTIand the predefined minimum uplink scheduling timing value is 2 or
 3. 58.The wireless device of claim 16 wherein the uplink grant schedulesmultiple uplink TTIs for the same wireless device.
 59. The wirelessdevice of claim 16 wherein the uplink grant comprises an indication ofone or more uplink TTIs for which the uplink grant is valid.
 60. Thewireless device of any one of claim 16 wherein an uplink part of specialsubframes can be used for uplink data transmission, and determining theuplink scheduling timing l comprises determining the uplink schedulingtiming l in such a manner that the uplink part of the special subframesare treated as uplink TTIs.
 61. The wireless device of claim 16 whereindetermining the uplink scheduling timing l comprises determining theuplink scheduling timing l in such a manner that the uplink part of thespecial subframes are not treated as uplink TTIs.
 62. The wirelessdevice of claim 16 wherein the configured TDD uplink/downlinkconfiguration is Long Term Evolution, LTE, TDD uplink/downlinkconfiguration 1, and determining the uplink scheduling timing lcomprises determining the uplink scheduling timing l such that: theuplink scheduling timing l is 3 if n=0; the uplink scheduling timing lis 5 if n=1 and if UpPTS contains PUSCH; the uplink scheduling timing lis 3 if n=4; the uplink scheduling timing l is 3 if n=5; the uplinkscheduling timing l is 5 if n=6 and if UpPTS contains PUSCH; and theuplink scheduling timing l is 3 if n=9.
 63. The wireless device of claim16 wherein the configured TDD uplink/downlink configuration is Long TermEvolution, LTE, TDD uplink/downlink configuration 2, and determining theuplink scheduling timing l comprises determining the uplink schedulingtiming l such that: the uplink scheduling timing l is 3 if n=3 and ifUpPTS contains PUSCH; the uplink scheduling timing l is 3 if n=4; theuplink scheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; andthe uplink scheduling timing l is 3 if n=9.
 64. The wireless device ofclaim 16 wherein the configured TDD uplink/downlink configuration isLong Term Evolution, LTE, TDD uplink/downlink configuration 3, anddetermining the uplink scheduling timing l comprises determining theuplink scheduling timing l such that: the uplink scheduling timing l is3 if n=0; the uplink scheduling timing l is 3 if n=1; the uplinkscheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; and theuplink scheduling timing l is 3 if n=9.
 65. The wireless device of claim16 wherein the configured TDD uplink/downlink configuration is Long TermEvolution, LTE, TDD uplink/downlink configuration 4, and determining theuplink scheduling timing l comprises determining the uplink schedulingtiming l such that: the uplink scheduling timing l is 3 if n=0; theuplink scheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; andthe uplink scheduling timing l is 3 if n=9.
 66. The wireless device ofclaim 16 wherein the configured TDD uplink/downlink configuration isLong Term Evolution, LTE, TDD uplink/downlink configuration 5, anddetermining the uplink scheduling timing l comprises determining theuplink scheduling timing l such that: the uplink scheduling timing l is3 if n=8 and if UpPTS contains PUSCH; and the uplink scheduling timing lis 3 if n=9.
 67. The wireless device of claim 16 wherein determining theuplink scheduling timing l comprises determining the uplink schedulingtiming l based on the configured TDD uplink/downlink configuration andan uplink index comprises the uplink grant received in the TTI n. 68.The wireless device of claim 16 wherein the TTI n and the TTI n+l are 1millisecond TTIs.
 69. The radio access node of claim 33 wherein theuplink scheduling timing l is a smallest integer number of TTIs that islarger than or equal to a predefined minimum uplink scheduling timingvalue such that n+l is an uplink TTI and the predefined minimum uplinkscheduling timing value is 2 or
 3. 70. The radio access node of claim 33wherein the uplink grant schedules multiple uplink TTIs for the samewireless device.
 71. The radio access node of claim 33 wherein theuplink grant comprises an indication of one or more uplink TTIs forwhich the uplink grant is valid.
 72. The radio access node of claim 33wherein an uplink part of special subframes can be used for uplink datatransmission, and the uplink scheduling timing l is determined in such amanner that the uplink part of the special subframes are treated asuplink TTIs.
 73. The radio access node of claim 33 wherein the uplinkscheduling timing l is determined in such a manner that the uplink partof the special subframes are not treated as uplink TTIs.
 74. The radioaccess node of claim 33 wherein the configured TDD uplink/downlinkconfiguration is Long Term Evolution, LTE, TDD uplink/downlinkconfiguration 1, and: the uplink scheduling timing l is 3 if n=0; theuplink scheduling timing l is 5 if n=1 and if UpPTS contains PUSCH; theuplink scheduling timing l is 3 if n=4; the uplink scheduling timing lis 3 if n=5; the uplink scheduling timing l is 5 if n=6 and if UpPTScontains PUSCH; and the uplink scheduling timing l is 3 if n=9.
 75. Theradio access node of claim 33 wherein the configured TDD uplink/downlinkconfiguration is Long Term Evolution, LTE, TDD uplink/downlinkconfiguration 2, and: the uplink scheduling timing l is 3 if n=3 and ifUpPTS contains PUSCH; the uplink scheduling timing l is 3 if n=4; theuplink scheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; andthe uplink scheduling timing l is 3 if n=9.
 76. The radio access node ofclaim 33 wherein the configured TDD uplink/downlink configuration isLong Term Evolution, LTE, TDD uplink/downlink configuration 3, and: theuplink scheduling timing l is 3 if n=0; the uplink scheduling timing lis 3 if n=1; the uplink scheduling timing l is 3 if n=8 and if UpPTScontains PUSCH; and the uplink scheduling timing l is 3 if n=9.
 77. Theradio access node of claim 33 wherein the configured TDD uplink/downlinkconfiguration is Long Term Evolution, LTE, TDD uplink/downlinkconfiguration 4, and: the uplink scheduling timing l is 3 if n=0; theuplink scheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; andthe uplink scheduling timing l is 3 if n=9.
 78. The radio access node ofclaim 33 wherein the configured TDD uplink/downlink configuration isLong Term Evolution, LTE, TDD uplink/downlink configuration 5, and: theuplink scheduling timing l is 3 if n=8 and if UpPTS contains PUSCH; andthe uplink scheduling timing l is 3 if n=9.
 79. The radio access node ofclaim 33 wherein the uplink scheduling timing l is determined based onthe configured TDD uplink/downlink configuration and an uplink indexcomprised in the uplink grant in the TTI n.
 80. The radio access node ofclaim 33 wherein the TTI n and the TTI n+l are 1 millisecond TTIs.